A wearable device, such as a ring scanner, generally comprises a scanning unit coupled to a computing unit. The scanning unit acquires data and transmits the data to the computing unit via a coupling arrangement. One conventional coupling arrangement is a wired cord that is generally helical-shaped (e.g., a circular spiral). The cord comprises one or more wires covered in an insulating material, such as plastic or rubber. An advantage of forming the cord as a helix is that a length of the cord is reduced by winding the cord into compact coils. If the reduced length is insufficient to meet a user's needs, the cord can be stretched to its full length. The cord generally has elastic properties enabling it to return to a relaxed state when not acted upon by pulling forces.
FIG. 1 shows a perspective view of a mobile device 100. The device 100 includes a scanning arrangement 110 coupled to a triggering arrangement 120 and a cord 134. The scanning arrangement 110 may be a bar code scanner, an infrared sensor, an RFID reader, etc. The triggering arrangement 120 may include a trigger button 122 and a strap 124. As shown in FIG. 1, the cord 130 may include a helical section 134. A proximal end of the cord (not shown) is coupled to a computing unit worn by the user. For example, the computing unit can be worn on a wrist or a forearm, while the device 100 is worn on a finger.
Despite its advantages, a helical cord may be a potential source of inconvenience to the user. For example, if the computing unit is worn on the forearm, the cord 130 may be stretched to a length that makes the cord 130 uncomfortable. The stretching causes the cord 130 to be in a constant state of tension, limiting or making difficult movement of the device 100. As a result, the user may be required to exert a large amount of effort to position or maneuver the device 100. Over an extended period of use, this may result in user fatigue. In addition, friction from the cord 130 may cause further discomfort to the user. Another disadvantage is that if the computing unit is worn closer to the device 100 (e.g., at the wrist), the cord 130 can bow outward, obstructing the user's view of the computing unit and potentially getting tangled with itself or with another object. The force and length of cord required is also controlled by the diameter of the helix. If a low force, long cord is required in a short distance, it may be necessary to create a large diameter helix. The large diameter then presents itself as a hook point which could cause the user inconvenience.